LAUSR

Abstract Background: To better understand the maintenance of chronic fatigue syndrome (CFS), a valid and reliable measure of cognitive and behavioural responses to symptoms is required. Such a measure could also assess beliefs and coping behaviours in the context of fatigue in other somatic conditions. Aims: We aimed to establish the psychometric properties of both the Cognitive and Behavioural Responses Questionnaire (CBRQ) and its shortened version (CBRQ-S) in adolescents with CFS. Method: The full questionnaire was completed by a clinical cohort of adolescents (n = 121) presenting to specialist CFS units in the UK. Results: Both the CBRQ and CBRQ-S had good internal consistency. The CBRQ scores were strongly associated with depression, anxiety, school and social functioning, but weakly associated with fatigue and physical functioning, providing evidence of validity. Conclusion: Both the 40-item and the 18-item versions of the CBRQ were found to be reliable and valid in adolescents with CFS. To minimize unnecessary burden, the 18-item version is favoured. Using this assessment tool in future studies, including intervention studies, may help to better target interventions during clinical practice and improve outcomes.